Seal protector for air filtering apparatus

ABSTRACT

Apparatus to remove dust, fibers, lint or other undesirable particles from air. Air ladened with dust, lint or other undesirable matter is drawn into a filtering housing to contact the surface of a rotatable screen-covered drum. The air passes through the drum while the particles remain on the drum surface. The air passes from a higher pressure area exterior of the drum into a lower pressure area within the center of the drum and is conveyed away. The particles are retained on the exterior surface of the drum which is covered by the fine mesh screen. The particles, which form a bat, are then separated from the rotating drum surface by being moved into contact with a smooth compressor roll cooperating with a flighted doffing to lift away the bat from the drum and drop it to a collection zone. Fixed rubber seals are located to contact the rotating edges of the drum. A metal seal protector plate is provided adjacent the area where the flighted doffing rolls would contact the rubber seals to minimize the wear on such seals during normal operation to extend the useful life of the seals and the machine.

BACKGROUND OF THE INVENTION

This invention relates to apparatus for separating and recoveringparticles such as dust, fibers and lint from carrier air. The atmospherein and around textile and other treating facilities may often carryundesirable particles of this type. To remove and recover theseparticles, the air in such zones must be continually filtered. Variousmachines and methods have been designed to eliminate undesirableparticles of these types from air in these zones. One such device isdescribed in U.S. Pat. No. 3,525,198, issued Aug. 25, 1970 to Joseph C.Nietzel. Another approach is disclosed in the commercially availableFIBR-A-FILTER® air filtering system sold by The Continental Conveyor andEquipment Company, Inc. Both of these systems utilize a rotating screendrum, positioned with ducting which conveys unfiltered air from a highpressure zone to a clean air discharge zone of lower pressure. Bothutilize the rotating drum for supporting a filtering screen forseparating the air from the particles it carries. Both utilize a smoothcompression roller in association with a doffing roller with urethaneflights to remove product bat discharge from the rotating drum. And bothutilize rubber air seals secured to the drum-containing housing. Theseseals contact the opposite circumferential ends of the drum to precludeparticle laden air from passing into the center of the drum via theends, rather than through the filtering screen.

SUMMARY OF THE INVENTION

An object of the instant invention is thus to increase the efficiency ofknown air filtering machines by insuring the more complete removal ofparticles from particle ladened air and to extend the useful life ofparts of air filtering machines.

These and other objects of the present invention are obtained throughthe use of durable protector plates adjacent the rubber seals at thecircumferential ends of the drum surface in the zone where the flighteddoffing roll continuously contacts the drum surface for cleaningpurposes. Without such protector plates, the flexible doffer flightswould continually contact, abrade and deteriorate the rubber seals thusrequiring periodic replacement to insure the preclusion of the flow ofparticle ladened air into the clean air zone through paths other thanthrough the exterior screened surface of the drum. The protector platestherefore reduce down time and maintenance costs while extending thelife of these rubber seals. The plates thus contribute to greaterfiltering efficiency of the machinery.

DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which illustrate the invention,

FIG. 1 is a side elevational view of air filtering machinery constructedin accordance with the instant invention with a part of the housing sideframe removed to show internal constructions thereof.

FIG. 2 is a top plan view of the air filtering machinery of FIG. 1 butwith the housing top removed.

FIG. 3 is an isometric showing of the drum and associated rollers anddrives.

FIG. 4 is an enlarged view of the end sealing means, drum and doffingroller shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a side elevational view of the basic elements of the airfiltering system which constitutes the preferred embodiment for theutilization of the instant invention. At one end of the housing 10 is anair inlet duct 12, shown substantially radially with respect to thefiltering drum 14, for drawing the particle ladened air intocommunication with the filtering drum 14 for cleaning. An outlet duct 16is provided and shown substantially parallel with the axis of therotatable drum for drawing away clean, filtered air from within thefiltering drum and chamber 20 in which the drum is located. Suitablesensors 22 and 24 and drive means 26 are provided in association withthe ducts for maintaining the proper pressure relationship between theinlet and the outlet ducts for causing the flow of particle ladened airto the drum and clean air from the interior of the drum.

A product bat discharge area is provided adjacent one segment of therotating drum, shown for illustrative purposes at the four o'clockposition in FIG. 1. By product bat it is meant the accumulated dust,lint and fibers or other particulate material removed from the incomingair, gathered on the screen 28 or other filtering media of the drum andremoved to an accumulation zone.

The drum and ducts are supported in proper orientation with each otherby side housing frames 30 and top and bottom housing frames 32 and 34 inairtight relationship except for communication with the ducts andproduct bat discharge and accumulation zone if external from thehousing. Further, the drum interior must be appropriately sealed fromthe space within the housing to preclude the movement of particleladened air through to a lower pressure zone, and to exterior of themachine other than through the cylindrical screen which constitutes thefilter. This is desirable since all incoming air must be filteredthrough the screen surface of the rotating drum.

The drum is mounted on a rotating shaft 36 and journaled in said housingframes 30 of the housing. On this rotating shaft 36 are a pair ofbushings 38 held in position through set screws or other appropriatemeans. A plurality of spokes 40 are mounted to the bushing forsupporting the end rings 42 of the drum which in turn mount a grid workof axial rods and rings to which is mounted the fine metal screen 28 forthe filtering of the incoming air. Axial and cylindrical straps are heldto the cagework structure of the drum and support the screen in theremovable orientation with respect thereto for cleaning and replacement.

The air discharge end 54 and other end 52 of the drum are locatedadjacent the end surfaces of the housing with seal means 56 mounted toan appropriate housing part 58 as by bolt 60 to contact the cylindricalends of the rotating drum to preclude the movement of particle ladenedair to the lower pressure zone and exit ducts through an avenue otherthan the filtering screen surface of the drum. This is because movementof particle ladened air to the lower pressure zone other than throughthe screen would permit particle ladened air to be removed from thesystem without the appropriate filtering action occurring. The preferredsealing means normally take the form of modified Z-shaped rubber seals56 received by bolts and adhered to both ends of the housing adjacentthe drum ends. They are positioned circumferentially entirely around andentirely in contact with each edge of the cylindrical drum surface.

Located adjacent one portion of the cylindrical drum surface is asmooth, metal compression seal roller 62 and the doffing roller 64 withflexible urethane flights 66 to effect removal of the product bat 18from the drum surface. Supplemental seals 70 and 72 extend the length ofthe drum adjacent these two rollers to preclude particle ladened airfrom escaping from the housing. The lower seal 70 is constructed ofrubber and is mounted to the bottom frame member 34 in contact with aseal roller 62. The upper seal or scroll 72 is constructed preferably ofmetal and contacts the flexible flights 66 of the doffing roller 64 tocreate an air seal in this area.

During the normal operation of prior art devices as described above, thebat of filtered product which accumulates on the revolving screen drumis discharged from the machine by means of a smooth compression rollerand a flighted doffing roller. The discharge is a mere dropping of thebat to an accumulation zone therebeneath.

On occasion due to various reasons the product bat will not dischargeand fall from the bat discharge zone along and following the normaldischarge path as shown by the arrow but instead will stay attached toor follow the flighted doffing roller during its rotation. As a resultof this action the seal scroll 72 may become clogged or damaged by thebat being forced by it through the sealing passage. Additionally theproduct bat may re-enter the machine to contact the drum and cause themachine to choke which will cause other damage and operational shutdown.

To prevent this action a supplemental wiper roll 74 has been devised andinstalled to prevent the discharging bat from following an abnormal pathbetween the seal scroll, doffer roller and the drum. The wiper roller,constructed of a rotating steel shaft 76 and rigid flights 78,constructed of metal or other rigid material, deflects and wipes each ofthe flights of the doffing roller during mutual interaction of thesesets of flights, preferably in the same direction with wiper rolloperating at a greater speed. Due to this action the bat is not allowedto stay attached to the flighted doffing roller but is mechanicallyremoved therefrom due to the location of the wiper roller and thus theproduct bat is forced to assume the normal discharge path. In thepreferred orientation, the doffer roll flights deform when they contactthe drum, seal roller, scroll and wiper roller. Remote from the drum thedoffer flights contact the flights of the wiper roll with the wiper rollflights positioned to extend into the doffer flights to produce anadequate wiping action.

The wiper roller is constructed of a round rotatable steel shaft 76 witha number of rigid bars or flights 78, preferably of steel, rigidlyattached thereto and running longitudinal to the shaft length andperpendicular to the shaft centerline. The wiper roller's design andmaterial is not limited to that described above.

The wiper roller is supported on both ends by means of bearings and iscaused to rotate, as for example by means of a drive from the flightedroller. FIG. 3 illustrates the drive shafts for the drum, the sealroller shaft 82, the doffing roller shaft 84 and wiper roller shaft 76with appropriate gears, chains and motor 88 for effecting their relativerotating motion one with respect to the other as shown by the arrows inFIG. 1.

During the operation of earlier machines of the type referred to above,flights of the doffing roller rotates in contact against the filteringscreen of the drum as well as stationary rubber seals in the batdischarge zone. This action in time prematurely would wear out thestationary rubber seals and, consequently, undesirably allows particleladened air to move to the lower pressure zone and air exit duct at thiswear point. The movement of air through this path will reduce theefficiency of the machine.

To prevent this undesirable wearing action a seal protector plate 92 hasbeen devised and installed at both open ends of the revolving drumcovering a small arc adjacent to where the doffer flights wouldotherwise contact the drum. This protector plate is located between bothstationary rubber seals 56 and the doffing roller flights 66 thereforepreventing the above described and undesirable wearing action on theseals. It is mounted on the side frames and extends inwardly toward thecenter of the drum to a distance further than the inwardly extendingseal. The protector plate can be held in position by attachment to theend housing frame 30 or other suitable part of the apparatus. Theprotector plate is preferably made of a durable material such as longwearing carbon steel construction. It is rigid enough to cause the edgesof each doffing roll flight to deform, as shown in FIG. 4, at its edgesonly to permit doffing roll contact only at the screen but not at theedge seals.

While the instant invention is disclosed as being carried out in apreferred embodiment, it is not intended to be so limited but to beprotected broadly within the spirit and scope of the appended claims.

I claim:
 1. Apparatus for filtering air including a chamber having anair inlet and an air outlet,a drum mounted for rotation within saidchamber, filtering media secured to the cylindrical surface of saiddrum, means to cause a flow of particle ladened air into said chamberfrom said air inlet and into contact with said filtering media and tocause a flow of clean air from within said drum to exterior of said drumand said chamber through said air outlet, seal means mounted on saidchamber adjacent said drum to preclude the flow of particle ladened airto exterior of said chamber other than through said filtering media,means to remove bat formed of filtered particles from the filteringmedia on the surface of said drum, said last-mentioned means including acompression seal roller mounted for rotation out of contact with saiddrum and a doffing roller having flexible flights and mounted forrotation in contact with said drum to assist in removing bat from saiddrum and means for protecting said seal means formed of durable materialfixedly positioned between said seal means and the flights of saiddoffer roller adjacent the edge of said drum to eliminate wear on saidseal means by the edges of the flights of said doffing rollers whenrotating there adjacent.
 2. The apparatus as set forth in claim 1wherein said protecting means comprises sheet metal secured to a portionof the apparatus and extending to a length to deform the edges of thedoffer roll flights which would otherwise contact said seal means. 3.The apparatus as set forth in claim 1 wherein said seal means and saidprotecting means are fixedly positioned adjacent the edges of said drumwith said protecting means extending inwardly toward the center of thedrum greater distances than said seal means.